This invention relates to a process for production of aluminum oxide by heating compounds containing aluminum and fluorine in a gas stream containing oxygen or H.sub.2 O.
For production of metallic aluminum, it has been a conventional practice that alumina is produced by leaching of raw materials, such as bauxite, containing aluminum with sodium hydroxide, then hydrolysis of thus obtained sodium aluminate to obtain aluminum hydroxide which is calcined to obtain alumina, and then the powder alumina is subjected to electrolytic reduction in a fused cryolite bath to obtain metallic aluminum.
However, the following disadvantages are found in the conventional process of alumina production.
(1) A large amount of energy is required for concentration of sodium hydroxide diluted in the hydrolysis process in order to recover the used sodium hydroxide. PA1 (2) Problems are caused by disposal on the sea of leached residues (red mud) from a view point of environmental protection.